Quiz - 17 - Diving Knowledge Workbook - Diving Physiology

[EFX]

I did get the correct answer on the quiz. But I assume you know my question refers to a question where all 4 are correct but you don't select "all of the above". All in good fun, but curious as to why some questions would have 4 correct answers and you are to choose one. Doesn't seem questions like that need to exist. They're teaching you how to outsmart multiple choice wordings rather than to check your knowledge of the material. I learned how to do that 50 years ago in Jr. High.

If I remember correctly the instructions at the top of the PADI quiz said to choose one answer that best answers the question. So, it's not about outsmarting the choice of wording but understanding and following the directions. But, I get it. The inclusion of "all of the above are correct" throws an additional wrinkle into the testing. BTW, semantics aside, there are not four correct answers. There is only one correct answer per the instructions. Including an "all of the above" choice allows you to select the one correct answer that includes multiple correct statements. In order to choose that answer you have to know the material. I had a college professor that emphatically gave this advice before taking exams: "Read the incestuous question before answering."

 

[TMHeimer]

However, "all of the above" was not really a valid option on this question because CO is not an inert gas.

Right. That was one way I figured only c. was correct. Someone mentioned it depends on what you call "inert"-- too deep for me, so I figured like nitrogen, it was inert. Also didn't recall reading about a sedating effect, tough I suppose someone would find reason to say it does--I don't know.

 

[DandyDon]

Someone mentioned it depends on what you call "inert"

That was me, but of course CO is not inert as it can breakdown to C and O2, or it can oxidize to CO2, as I mentioned there.

I figured like nitrogen, it was inert.

Nope. Nitrogen can react with other elements.

The inert gases are helium, neon, argon, krypton, xenon and radon.

 

[boulderjohn]

Nope. Nitrogen can react with other elements.
The inert gases are helium, neon, argon, krypton, xenon and radon.

That is absolutely correct. Unfortunately, scuba terminology often screws that up by using "inert" to describe nitrogen, which, unlike oxygen, does not do any of those possible reactions during respiration.

 

[Storker]

Nitrogen can react with other elements.

The inert gases are helium, neon, argon, krypton, xenon and radon.

Nitrogen (N2) isn't formally inert, but for most practical purposes it's inert. You need a LOT of energy to break the triple bond between the atoms in N2

 

[TMHeimer]

Nitrogen (N2) isn't formally inert, but for most practical purposes it's inert. You need a LOT of energy to break the triple bond between the atoms in N2

Yes. I figured the manuals meant inert as far as being used by the body, like oxygen is.

 

[DandyDon]

Yes. I figured the manuals meant inert as far as being used by the body, like oxygen is.

I don't know how Nitrogen is handled and processed by industries but it certainly used in the human body. We don't absorb it by breathing, but it is reactive in other ways: "Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids (DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere."

I remember one time decades ago when I was applying anhydrous ammonia to a field by plowing it into moist soil from a big tank behind my tractor when the hose broke on a turn spraying a cloud of it upwind of me. I almost panicked thinking I needed I exit that tractor and run to get upwind before it burned my eyes and lungs killing me on the spot. Then I caught myself and turned the rig around to park the tractor upwind and exited calmly to turn the valve off.

 

[Akimbo]

Nitrogen (N2) isn't formally inert, but for most practical purposes it's inert.

The US Navy uses (used?) "biologically inert" to avoid confusion with noble elements. That convention sticks with me today for diving physiology discussions even though it is not technically correct -- Nitrous Oxide (N2O) for example. Maybe ScubaBoard should coin a better phrase?

 

[Storker]

I don't know how Nitrogen is handled and processed by industries but it certainly used in the human body. We don't absorb it by breathing, but it is reactive in other ways: "Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids (DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere."

You seem to be conflating the element nitrogen (N) with the gas nitrogen (N2). They are not the same.

 

[Storker]

The US Navy uses (used?) "biologically inert" to avoid confusion with noble elements. That convention sticks with me today for diving physiology discussions even though it is not technically correct -- Nitrous Oxide (N2O) for example. Maybe ScubaBoard should coin a better phrase?

I think that "biologically inert" is a genius term. IMNSHO it's very much technically correct.

Nitrogen gas (N2) is extremely inert, especially in biology. It wasn't until Birkeland and Eyde invented their - rather energy-intensive - process that Man was able to break the triple bond in an efficient manner. For all practical purposes - perhaps except high-temperature combustion processes - N2 is inert.